Entrance Papers

WBJEE-2011

CHEMISTRY

DESCRIPTIVE TYPE QUESTIONS

Full Marks--10

1. The bacterial growth follows the rate law, dN/dt=KN where 'K' is a constant and 'N' is the number of bacteria at any time. If the population of bacteria (no. of cell) is doubled in 5 minutes, find the time by which the population will be eight times of the initial one.


2. In 'x' ml 0.3 (N) HCl, addition of 200 ml distilled water on addition of 100 ml 0.1 (N) NaOH, gives same final acid strength. Determine 'x'.


3. Compound A treated with NaNH2 followed by CH3CH2Br gave compound B. Partial hydrogenations of compound B produce compound C, which on ozonolysis gave a   carbonyl compound D, (C3H6O). Compound D did not respond to iodoform test with I2/KI and NaOH. Find out the structure of A,B,C & D. 


4. An organic compound with molecular formula C9H10O forms 2,4-DNP derivative, reduces Tollen's reagent and undergoes Cannizzaro reaction. On vigorous oxidation it gives a dicarboxylic acid which is used in the preparation of terylene. Identify the Organic compound.


5. Deep blue CuSO4,5H2O is converted to a bluish white salt at 100 Degree Celsius . At 250 degree Celsius and 750 degree Celsius it is then transformed to a white powder and black material respectively. Identify the salts.